Test Code DD
D-Dimer, Quantitative, Plasma

Performing Laboratory

Methodology

Reference Values

Test Classification and CPT Coding

85379

Specimen Required

Container/Tube: Light blue-top (3.2%
sodium citrate) tube

Specimen: 0.5 mL citrated plasma

Transport Temperature: Frozen

Collection Instructions:

If the light blue top tube is the only tube to be drawn and
will be collected using a butterfly set, a “discard”
tube (either a plain[non-additive] or light blue) must be partially
drawn just to completely fill the collection tubing with blood
before collecting the light blue top for testing. Failure to
perform this step will result in an under-filled tube that the
laboratory will reject.

Allow blood to fill the tube completely to the line on the
tube. The ratio of blood to anticoagulant is critical in
coagulation testing and at least a 90% fill is required.

Immediately mix the specimen by gently inverting the tube 4-6
times to completely mix with the anticoagulant. Failure to
perform this can result in a clotted sample, which is unacceptable
for testing.

If centrifugation of the specimen cannot be performed
immediately after collection, whole blood can be kept in the blue
top tube at room temperature (18-24° C) for up to 4 hours for
the APTT and up to 24 hours for a PT/INR. For additional
coagulation assays, whole blood cannot be refrigerated or
frozen.

If centrifugation is possible, and transport to the lab will
not occur within 1 hour, spin down, remove the plasma to a
clean plastic transport tube using a plastic transfer pipette, and
spin the plasma again. Remove the plasma with a clean plastic
transfer pipette to a fresh transport container and freeze
this citrated platelet-poor plasma immediately. A
double centrifuged specimen is critical for accurate results as
platelet contamination may cause spurious results. Each
coagulation assay requested should have its own vial of citrated
plasma, 1.0mL each.